He was diagnosed with a serious blood disorder and died of a stroke on 8 November 2004. But no post mortem examination was carried out as his widow Suha did not ask for one.

When in 2012 an investigation by al-Jazeera TV in conjunction with Swiss analysts in Lausanne found abnormal levels of polonium-210 on his personal effects, Suha Arafat called for her late husband's body to be exhumed.

France then launched a formal murder inquiry.

The Vaudois University Hospital Centre (CHUV) in Lausanne reported its findings last month, on the ninth anniversary of his death, saying its results "offer moderate backing for the theory of poisoning".

But a leaked report of Russia's initial tests on the same day said high radioactive penetration was "unsubstantiated". Weeks later, a source said the French report had ruled out the poisoning theory, and pointed towards a natural death.

Announcing its conclusions on Thursday, the head of Russia's Federal Medical-Biological Agency (FMBA), Vladimir Uiba, said "Yasser Arafat died not from the effects of radiation but of natural causes".

The agency had completed its work, he said, and there was general agreement with its findings. "Even the Swiss withdrew their statements and agreed with us, and the French confirmed our conclusions," Mr Uiba was quoted as saying by Interfax.